It is maybe overridden by a 3rd party software installed on your PC.
There was a case, when the Refresh function by using keyboard shortcut Shift+F9 on a desktop computer in the transaction /SAPAPO/RRP3 did not execute.
No error has been detected like that before, and also the refresh function could have been alternatively executed from menu or toolbar without problem.
At the end the root cause has been found: a 3rd party screen capture program has taken over the control of Shift + F9 in a Windows environment.
(searching on the internet, several other - SAP independent - case can be found with the same symptom caused by software for this functionality)
So if you prefer using the keyboard shortcut in SAP GUI for refresh the content in a transaction, check and disable the function for Shift+F9 in the 3rd party software. In the case mentioned above this has solved the issue.